Anticoagulation practices and the prevalence of major bleeding, thromboembolic events, and mortality in venoarterial extracorporeal membrane oxygenation: A systematic review and meta-analysis. J Crit Care. 2017;39:87-96. [PMID: 28237895 DOI: 10.1016/j.jcrc.2017.02.014]

Extracorporal Membrane Oxygenation in Massive Pulmonary Embolism

BACKGROUND

Massive pulmonary embolism (MPE) carries significant 30-day mortality risk, and a change in societal guidelines has promoted the increasing use of extracorporeal membrane oxygenation (ECMO) in the immediate management of MPE-associated cardiovascular shock. This narrative review examines the current status of ECMO in MPE.

METHODS

A literature review was performed from 1982 to 2022 searching for the terms "Pulmonary embolism" and "ECMO," and the search was refined by examining those publications that covered MPE.

RESULTS

In the patient with MPE, veno-arterial ECMO is now recommended as a bridge to interventional therapy. It can reliably decrease right ventricular overload, improve RV function, and allow hemodynamic stability and restoration of tissue oxygenation. The use of ECMO in MPE has been associated with lower mortality in registry reviews, but there has been no significant difference in outcomes between patients treated with and without ECMO in meta-analyses. Applying ECMO is also associated with substantial multisystem morbidity due to systemic inflammatory response, bleeding with coagulopathy, hemorrhagic stroke, renal dysfunction, and acute limb ischemia, which must be factored into the outcomes.

CONCLUSIONS

The application of ECMO in MPE should be combined with an aggressive interventional pulmonary interventional program and should strictly adhere to the current selection criteria.

Anti-Xa-guided Anticoagulation With Unfractionated Heparin and Thrombosis During Extracorporeal Membrane Oxygenation Support: A Systematic Review and Meta-analysis

OBJECTIVE

The initiation of extracorporeal membrane oxygenation (ECMO) triggers complex coagulation processes necessitating systemic anticoagulation. Therefore, anticoagulation monitoring is crucial to avoid adverse events such as thrombosis and hemorrhage. The main aim of this work was to analyze the association between anti-Xa levels and thrombosis occurrence during ECMO support.

DESIGN

Systematic literature review and meta-analysis (Scopus and PubMed, up to July 29, 2023).

SETTING

All retrospective and prospective studies.

PARTICIPANTS

Patients receiving ECMO support.

INTERVENTION

Anticoagulation monitoring during ECMO support.

MEASUREMENTS AND MAIN RESULTS

A total of 16 articles with 1,968 patients were included in the review and 7 studies in the meta-analysis (n = 374). Patients with thrombosis had significantly lower mean anti-Xa values (standardized mean difference -0.36, 95% confidence interval [CI] -0.62 to -0.11, p < 0.01). Furthermore, a positive correlation was observed between unfractionated heparin infusion and anti-Xa levels (pooled estimate of correlation coefficients 0.31, 95% CI 0.19 to 0.43, p < 0.001). The most common adverse events were major bleeding (42%) and any kind of hemorrhage (36%), followed by thromboembolic events (30%) and circuit or oxygenator membrane thrombosis (19%). More than half of the patients did not survive to discharge (52%).

CONCLUSIONS

This work revealed significantly lower levels of anti-Xa in patients experiencing thromboembolic events and a positive correlation between anti-Xa and unfractionated heparin infusion. Considering the contemplative limitations of conventional monitoring tools, further research on the role of anti-Xa is warranted. New trials should be encouraged to confirm these findings and determine the most suitable monitoring strategy for patients receiving ECMO support.

Mucosal bleeding while on venovenous extracorporeal membrane oxygenation in the setting of vitamin C deficiency

A major complication with extracorporeal membrane oxygenation (ECMO) is bleeding which can occur in up to 40% of cases and can be life-threatening. Minor bleeding may be overlooked and under-reported. While some of the underlying mechanisms such as platelet injury and anticoagulation therapy have been identified, several other factors are still under-researched. Here, we describe a unique case of a subtle mucosal membrane bleeding that is found to be associated with vitamin C deficiency while on treatment with ECMO. Investigating vitamin C levels may be useful in understanding causes of bleeding in some patients on ECMO therapy, particularly if there are risk factors for malnutrition.

Heparin Dosing Regimen Optimization in Veno-Arterial Extracorporeal Membrane Oxygenation: A Pharmacokinetic Analysis

BACKGROUND

Unfractionated heparin is administered in patients undergoing veno-arterial extracorporeal membrane oxygenation (VA-ECMO). Anticoagulation monitoring is recommended, with an anti-activated factor X (anti-Xa) targeting 0.3 to 0.7 IU/mL. Owing to heparin's heterogeneous pharmacokinetic properties, anti-Xa is unpredictable, generating a challenge in anticoagulation practices. The aim of this study was to build a pharmacokinetic model of heparin accounting for potential confounders, and derive an optimized dosing regimen for a given anti-Xa target.

METHODS

Adult patients undergoing VA-ECMO were included between January 2020 and June 2021. Anticoagulation was managed with an initial 100 IU/kg heparin loading dose followed by a continuous infusion targeting 0.2 to 0.7 IU/mL anti-Xa. The data were split into model development and model validation cohorts. Statistical analysis was performed using a nonlinear mixed effects modeling population approach. Model-based simulations were performed to develop an optimized dosing regimen targeting the desired anti-Xa.

RESULTS

A total of 74 patients were included, with 1703 anti-Xa observations. A single-compartment model best fitted the data. Interpatient variability for distribution volume was best explained by body weight, C-reactive protein and ECMO indication (post-cardiotomy shock or medical cardiogenic shock), and interpatient variability for elimination clearance was best explained by serum creatinine and C-reactive protein. Simulations using the optimized regimen according to these covariates showed accurate anti-Xa target attainment.

CONCLUSION

In adult patients on VA-ECMO, heparin's effect increased with serum creatinine and medical indication, whereas it decreased with body weight and systemic inflammation. We propose an optimized dosing regimen accounting for key covariates, capable of accurately predicting a given anti-Xa target.

Comparison of Outcomes in Patients Requiring Mechanical Circulatory Support Who Received Cangrelor in Addition to Anticoagulation Versus Anticoagulation Alone

OBJECTIVES

To evaluate the safety of cangrelor administered concurrently with heparin or bivalirudin in patients on mechanical circulatory support.

DESIGN

A single-center, retrospective cohort study of adult patients consecutively admitted between January 2016 and October 2020.

SETTING

A tertiary medical center.

PARTICIPANTS

Adult patients admitted to the cardiovascular intensive care unit put on mechanical circulatory support for acute myocardial infarction (AMI) or non-AMI indications. Patients who received cangrelor underwent percutaneous coronary intervention with stenting during the index event or within the last year.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the incidence of major bleeding, defined by the Extracorporeal Life Support Organization criteria, in patients with mechanical circulatory support receiving cangrelor plus anticoagulation with heparin or bivalirudin with or without aspirin versus patients who did not receive cangrelor. Sixty-eight patients were included in the study. Twenty-nine patients received cangrelor, and 39 did not. Cangrelor was not associated with an increase in major bleeding; however, the CI was wide (adjusted hazard ratio 1.93, 95% CI 0.61-6.11; p = 0.262).

CONCLUSIONS

Patients receiving cangrelor did not appear to be at higher risk of major bleeding compared to patients not receiving cangrelor. Larger trials should be conducted to better evaluate the safety of cangrelor in patients with mechanical circulatory support.

Evaluation of an aPTT guided versus a multimodal heparin monitoring approach in patients on extra corporeal membrane oxygenation: A retrospective cohort study

INTRODUCTION

Bleeding and thrombotic complications are common in extracorporeal membrane oxygenation (ECMO) patients and are associated with increased mortality and morbidity. The optimal anticoagulation monitoring protocol in these patients is unknown. This study aims to compare the incidence of thrombotic and hemorrhagic complications before and after a protocol change. In addition, the association between hemostatic complications, coagulation tests and risk factors is evaluated.

METHODS

This is a retrospective single center cohort study of adult ECMO patients. We collected demographics, ECMO parameters and coagulation test results. Outcomes of the aPTT guided and multimodal protocol, including aPTT, anti-Xa assay and rotational thromboelastometry were compared and the association between coagulation tests, risk factors and hemostatic complications was determined using a logistic regression analysis for repeated measurements.

RESULTS

In total, 250 patients were included, 138 in the aPTT protocol and 112 in the multimodal protocol. The incidence of thrombosis (aPTT: 14%; multimodal: 12%) and bleeding (aPTT: 36%; multimodal: 40%), did not significantly differ between protocols. In the aPTT guided protocol, the aPTT was associated with thrombosis (Odds Ratio [OR] 1.015; 95% confidence interval [CI] 1.004-1.027). In both protocols, surgical interventions were risk factors for bleeding and thrombotic complications (aPTT: OR 93.2, CI 39.9-217.6; multimodal OR 17.5, CI 6.5-46.9).

DISCUSSION

The incidence of hemostatic complications was similar between both protocols and surgical interventions were a risk factor for hemostatic complications. Results from this study help to elucidate the role of coagulation tests and risk factors in predicting hemostatic complications in patients undergoing ECMO support.

Bleeding and Thrombosis in Patients With Out-of-Hospital Ventricular Tachycardia/Ventricular Fibrillation Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation

BACKGROUND

Extracorporeal cardiopulmonary resuscitation improves outcomes after out-of-hospital cardiac arrest. However, bleeding and thrombosis are common complications. We aimed to describe the incidence and predictors of bleeding and thrombosis and their association with in-hospital mortality.

METHODS AND RESULTS

Consecutive patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest between December 2015 and March 2022 who met the criteria for extracorporeal cardiopulmonary resuscitation initiation at our center were included. Major bleeding was defined by the Extracorporeal Life Support Organization's criteria. Adjusted analyses were done to seek out risk factors for bleeding and thrombosis and evaluate their association with mortality. Major bleeding occurred in 135 of 200 patients (67.5%), with traumatic bleeding from cardiopulmonary resuscitation in 73 (36.5%). Baseline demographics and arrest characteristics were similar between groups. In multivariable analysis, decreasing levels of fibrinogen were independently associated with bleeding (adjusted hazard ratio [aHR], 0.98 per every 10 mg/dL rise [95% CI, 0.96-0.99]). Patients who died had a higher rate of bleeds per day (0.21 versus 0.03, P<0.001) though bleeding was not significantly associated with in-hospital death (aHR, 0.81 [95% CI. 0.55-1.19]). A thrombotic event occurred in 23.5% (47/200) of patients. Venous thromboembolism occurred in 11% (22/200) and arterial thrombi in 15.5% (31/200). Clinical characteristics were comparable between groups. In adjusted analyses, no risk factors for thrombosis were identified. Thrombosis was not associated with in-hospital death (aHR, 0.65 [95% CI, 0.42-1.03]).

CONCLUSIONS

Bleeding is a frequent complication of extracorporeal cardiopulmonary resuscitation that is associated with decreased fibrinogen levels on admission whereas thrombosis is less common. Neither bleeding nor thrombosis was significantly associated with in-hospital mortality.

Association of anti-factor Xa-guided anticoagulation with hemorrhage during ECMO support: A systematic review and meta-analysis

BACKGROUND

The use of extracorporeal membrane oxygenation (ECMO) is associated with complex hemostatic changes. Systemic anticoagulation is initiated to prevent clotting in the ECMO system, but this comes with an increased risk of bleeding. Evidence on the use of anti-Xa-guided monitoring to prevent bleeding during ECMO support is limited. Therefore, we aimed to analyze the association between anti-factor Xa-guided anticoagulation and hemorrhage during ECMO.

METHODS

A systematic review and meta-analysis was performed (up to August 2023).

PROSPERO

CRD42023448888.

RESULTS

Twenty-six studies comprising 2293 patients were included in the analysis, with six works being part of the meta-analysis. The mean anti-Xa values did not show a significant difference between patients with and without hemorrhage (standardized mean difference -0.05; 95% confidence interval [CI]: -0.19; 0.28, p = .69). We found a positive correlation between anti-Xa levels and unfractionated heparin dose (UFH; pooled estimate of correlation coefficients 0.44; 95% CI: 0.33; 0.55, p < .001). The most frequent complications were any type of hemorrhage (pooled 36%) and thrombosis (33%). Nearly half of the critically ill patients did not survive to hospital discharge (47%).

CONCLUSIONS

The most appropriate tool for anticoagulation monitoring in ECMO patients is uncertain. Our analysis did not reveal a significant difference in anti-Xa levels in patients with and without hemorrhagic events. However, we found a moderate correlation between anti-Xa and the UFH dose, supporting its utilization in monitoring UFH anticoagulation. Given the limitations of time-guided monitoring methods, the role of anti-Xa is promising and further research is warranted.

Heparin-free veno-arterial extracorporeal membrane oxygenation in lung transplantation: a retrospective cohort study

BACKGROUND

In lung transplantation (LTx) surgery, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) can provide mechanical circulatory support to patients with cardiopulmonary failure. However, the use of heparin in the administration of ECMO can increase blood loss during LTx. This study aimed to evaluate the safety of heparin-free V-A ECMO strategies.

METHODS

From September 2019 to April 2022, patients who underwent lung transplantation at the First Affiliated Hospital of Guangzhou Medical University were retrospectively reviewed. A total of 229 patients were included, including 117 patients in the ECMO group and 112 in the non-ECMO group.

RESULT

There was no significant difference in the incidence of thrombus events and bleeding requiring reoperation between the two groups. The in-hospital survival rate after single lung transplantation (SLTx) was 81.08%in the ECMO group and 85.14% in the Non-ECMO group, (P = 0.585). The in-hospital survival rate after double lung transplantation (DLTx) was 80.00% in the ECMO group and 92.11% in the Non-ECMO groups (P = 0.095).

CONCLUSIONS

In conclusion, the findings of this study suggest that the heparin-free V-A ECMO strategy in lung transplantation is a safe approach that does not increase the incidence of perioperative thrombotic events or bleeding requiring reoperation.

Impact of C-reactive Protein on Anticoagulation Monitoring in Extracorporeal Membrane Oxygenation

OBJECTIVE

To evaluate the impact of inflammation on anticoagulation monitoring for patients supported with extracorporeal membrane oxygenation (ECMO).

DESIGN

Prospective single-center cohort study.

SETTING

University-affiliated tertiary care academic medical center.

PARTICIPANTS

Adult venovenous and venoarterial ECMO patients anticoagulated with heparin/ MEASUREMENTS AND MAIN RESULTS: C-Reactive protein (CRP) was used as a surrogate for overall inflammation. The relationship between CRP and the partial thromboplastin time (PTT, seconds) was evaluated using a CRP-insensitive PTT assay (PTT-CRP) in addition to measurement using a routine PTT assay. Data from 30 patients anticoagulated with heparin over 371 ECMO days was included. CRP levels (mg/dL) were significantly elevated (median, 17.2; interquartile range [IQR], 9.2-26.1) and 93% of patients had a CRP of ≥5. The median PTT (median 58.9; IQR, 46.9-73.3) was prolonged by 11.3 seconds compared with simultaneously measured PTT-CRP (median, 47.6; IQR, 40.1-55.5; p < 0.001). The difference between PTT and PTT-CRP generally increased with CRP elevation from 2.7 for a CRP of <5.0 to 13.0 for a CRP between 5 and 10, 17.7 for a CRP between 10 and 15, and 15.1 for a CRP of >15 (p < 0.001). In a subgroup of patients, heparin was transitioned to argatroban, and a similar effect was observed (median PTT, 62.1 seconds [IQR, 53.0-78.5 seconds] vs median PTT-CRP, 47.6 seconds [IQR, 41.3-57.7 seconds]; p < 0.001).

CONCLUSIONS

Elevations in CRP are common during ECMO and can falsely prolong PTT measured by commonly used assays. The discrepancy due to CRP-interference is important clinically given narrow PTT targets and may contribute to hematological complications.

Gastrointestinal Bleeding in Extracorporeal Membrane Oxygenation Patients: A Comprehensive Analysis of Risk Factors and Clinical Outcomes

Background

Extracorporeal membrane oxygenation (ECMO) is an intervention for severe heart and lung failure; however, it poses the risk of complications, including gastrointestinal bleeding (GIB). Comprehensive analyses of GIB in patients undergoing ECMO are limited, and its impact on clinical outcomes remains unclear.

Methods

This retrospective study included 484 patients who received venovenous and venoarterial ECMO between January 2015 and December 2022. Data collected included patient characteristics, laboratory results, GIB details, and interventions. Statistical analyses were performed to identify risk factors and assess the outcomes.

Results

GIB occurred in 44 of 484 patients (9.1%) who received ECMO. Multivariable analysis revealed that older age (odds ratio [OR], 1.04; 95% confidence interval [CI], 1.01-1.06; p=0.0130) and need to change the ECMO mode (OR, 3.74; 95% CI, 1.75-7.96; p=0.0006) were significant risk factors for GIB, whereas no association was found with antiplatelet or systemic anticoagulation therapies during ECMO management. Half of the patients with GIB (22/44, 50%) underwent intervention, with endoscopy as the primary modality (19/22, 86.4%). Patients who underwent ECMO and developed GIB had higher rates of mortality (40/44 [90.9%] vs. 262/440 [59.5%]) and ECMO weaning failure (38/44 [86.4%] vs. 208/440 [47.3%]).

Conclusion

GIB in patients undergoing ECMO is associated with adverse outcomes, including increased risks of mortality and weaning failure. Even in seemingly uncomplicated cases, it is crucial to avoid underestimating the significance of GIB.

Detecting Oxygenator Thrombosis in ECMO: A Review of Current Techniques and an Exploration of Future Directions

Extracorporeal membrane oxygenation (ECMO) is a life-support technique used to treat cardiac and pulmonary failure, including severe cases of COVID-19 (coronavirus disease 2019) involving acute respiratory distress syndrome. Blood clot formation in the circuit is one of the most common complications in ECMO, having potentially harmful and even fatal consequences. It is therefore essential to regularly monitor for clots within the circuit and take appropriate measures to prevent or treat them. A review of the various methods used by hospital units for detecting blood clots is presented. The benefits and limitations of each method are discussed, specifically concerning detecting blood clots in the oxygenator, as it is concluded that this is the most critical and challenging ECMO component to assess. We investigate the feasibility of solutions proposed in the surrounding literature and explore two areas that hold promise for future research: the analysis of small-scale pressure fluctuations in the circuit, and real-time imaging of the oxygenator. It is concluded that the current methods of detecting blood clots cannot reliably predict clot volume, and their inability to predict clot location puts patients at risk of thromboembolism. It is posited that a more in-depth analysis of pressure readings using machine learning could better provide this information, and that purpose-built imaging could allow for accurate, real-time clotting analysis in ECMO components.

A review of pre-hospital extracorporeal cardiopulmonary resuscitation and its potential application in the North East of England

Patients in the UK who suffer an out-of-hospital cardiac arrest are treated with cardiopulmonary resuscitation in the pre-hospital environment. Current survival outcomes are low in out-of-hospital cardiac arrest. Extracorporeal cardiopulmonary resuscitation is a technique which is offered to patients in specialised centres which provides better blood flow and oxygen delivery than conventional chest compressions. Shortening the interval between cardiac arrest and restoration of circulation is associated with improved outcomes in extracorporeal cardiopulmonary resuscitation. Delivering extracorporeal cardiopulmonary resuscitation in the pre-hospital environment can shorten this interval, improving outcomes in out-of-hospital cardiac arrest. This article will review recently published studies and summarise studies currently being undertaken in pre-hospital extracorporeal cardiopulmonary resuscitation. It will also discuss the potential application of a pre-hospital extracorporeal cardiopulmonary resuscitation programme in the North East of England.

Extracorporeal membrane oxygenation in Jehovah's Witness patients: Case report, literature review, and summary of recommendations

Extracorporeal Membrane Oxygenation (ECMO) is commonly associated with a high blood transfusion requirement. Jehovah's Witness patients present a particular challenge. The impossibility of transfusing blood cells and starting anticoagulation treatment are common contraindications for this supportive measure. Here we report the case of a Jehovah's Witness patient with refractory hypoxemia due to influenza A H1N1 pneumonia who required venovenous ECMO for 11 days. We describe the use of a bloodless approach to reduce the waste of blood, avoiding anticoagulation, and improving red blood cell production. We then summarize the current literature on the use of ECMO in Jehovah's Witness patients and, finally, we propose some recommendations for their management.

Current status of ECMO for massive pulmonary embolism

Massive pulmonary embolism (MPE) carries significant 30-day mortality and is characterized by acute right ventricular failure, hypotension, and hypoxia, leading to cardiovascular collapse and cardiac arrest. Given the continued high mortality associated with MPE, there has been ongoing interest in utilizing extracorporeal membrane oxygenation (ECMO) to provide oxygenation support to improve hypoxia and offload the right ventricular (RV) pressure in the belief that rapid reduction of hypoxia and RV pressure will improve outcomes. Two modalities can be employed: Veno-arterial-ECMO is a reliable process to decrease RV overload and improve RV function, thus allowing for hemodynamic stability and restoration of tissue oxygenation. Veno-venous ECMO can support oxygenation but is not designed to help circulation. Several societal guidelines now suggest using ECMO in MPE with interventional therapy. There are three strategies for ECMO utilization in MPE: bridge to definitive interventional therapy, sole therapy, and recovery after interventional treatment. The use of ECMO in MPE has been associated with lower mortality in registry reviews, but there has been no significant difference in outcomes between patients treated with and without ECMO in meta-analyses. Considerable heterogeneity in studies is a significant weakness of the available literature. Applying ECMO is also associated with substantial multisystem morbidity due to a systemic inflammatory response, hemorrhagic stroke, renal dysfunction, and bleeding, which must be factored into the outcomes. The application of ECMO in MPE should be combined with an aggressive pulmonary interventional program and should strictly adhere to the current selection criteria.

Discordance among assays for monitoring? Anticoagulation during extracorporeal life support

OBJECTIVES

The optimal method for monitoring of anticoagulation in patients on extracorporeal life support (ECLS) is unknown. The objective of this study was to assess the relationship between anti-factor Xa level (anti-Xa; IU/mL) and activated partial thromboplastin time (aPTT; seconds) for monitoring intravenous unfractionated heparin anticoagulation in adult ECLS patients.

METHODS

Charts of all adult patients cannulated for ECLS from 2015 through 2017 were reviewed and laboratory and heparin infusion data were extracted for analysis. Time matched pairs of anti-Xa and aPTT were considered concordant if both laboratory values were within the same clinically utilized range. A hierarchical logistic regression model was used to determine factors associated with discordance while accounting for patient level effects.

RESULTS

A total of 1016 paired anti-Xa and aPTT values from 65 patients were evaluated. 500 (49.2%) paired samples were discordant with a degree of variability on linear regression (r2 = 0.315). The aPTT fell into a higher therapeutic range compared to the anti-Xa in 31.6% and lower in 17.3%. Logistic regression demonstrated that discordance was independently associated with time from initiation of ECLS (OR 1.17 per day, p < 0.001), average heparin infusion rate (OR 1.25 per U/kg/hr, p < 0.001), and INR (OR 3.22, p < 0.001).

CONCLUSIONS

Nearly half of all aPTT and anti-Xa values were in discordant ranges and discordance is more likely as the time on ECLS and the INR level increase. The use of either assay in isolation to guide heparin anticoagulation may lead to misestimation of the degree of anticoagulation in complex ECLS patients.

Comparison of clinical outcomes with cangrelor plus aspirin versus oral dual antiplatelet therapy in patients supported with venoarterial extracorporeal membrane oxygenation

BACKGROUND

Patients with refractory cardiogenic shock from an acute myocardial infarction may receive percutaneous coronary intervention (PCI) and require the use of venoarterial extracorporeal membrane oxygenation (VA-ECMO). The purpose of this study was to compare bleeding and thrombotic events in patients treated with cangrelor plus aspirin versus oral dual antiplatelet therapy (DAPT) while supported with VA-ECMO.

METHODS

We conducted a retrospective review of patients who received PCI, were supported with VA-ECMO, and were treated with either cangrelor plus aspirin or oral DAPT from February 2016 through May 2021 at Allegheny General Hospital. The primary objective was the incidence of major bleeding, defined as Bleeding Academic Research Consortium (BARC) type 3 or greater. The incidence of thrombotic events was a secondary objective.

RESULTS

Thirty-seven patients were included, 19 in the cangrelor plus aspirin group, and 18 in the oral DAPT group. All the patients in the cangrelor group received a dose of 0.75 mcg/kg/min. Major bleeding occurred in 7 patients (36.8%) in the cangrelor group compared to 7 patients (38.9%) in the oral DAPT group (p = 0.90). No patient developed stent thrombosis. Two patients (10.5%) in the cangrelor group had a thrombotic event versus 3 patients (16.7%) in the oral DAPT group (p = 0.66).

CONCLUSIONS

Bleeding and thrombotic events were comparable between patients receiving cangrelor plus aspirin versus oral DAPT while on VA-ECMO.

Artificial placenta support of extremely preterm ovine fetuses at the border of viability for up to 336 hours with maintenance of systemic circulation but reduced somatic and organ growth

Introduction: Artificial placenta therapy (APT) is an experimental life support system to improve outcomes for extremely preterm infants (EPI) less than 1,000 g by obviating the need for pulmonary gas exchange. There are presently no long-term survival data for EPI supported with APT. To address this, we aimed to maintain 95d-GA (GA; term-150d) sheep fetuses for up to 2 weeks using our APT system. Methods: Pregnant ewes (n = 6) carrying singleton fetuses underwent surgical delivery at 95d GA. Fetuses were adapted to APT and maintained for up to 2 weeks with constant monitoring of key physiological parameters and extensive time-course blood and urine sampling, and ultrasound assessments. Six age-matched in-utero fetuses served as controls. Data were tested for group differences with ANOVA. Results: Six APT Group fetuses (100%) were adapted to APT successfully. The mean BW at the initiation of APT was 656 ± 42 g. Mean survival was 250 ± 72 h (Max 336 h) with systemic circulation and key physiological parameters maintained mostly within normal ranges. APT fetuses had active movements and urine output constantly exceeded infusion volume over the experiment. At delivery, there were no differences in BW (with edema in three APT group animals), brain weight, or femur length between APT and in-utero Control animals. Organ weights and humerus lengths were significantly reduced in the APT group (p < 0.05). Albumin, IGF-1, and phosphorus were significantly decreased in the APT group (p < 0.05). No cases of positive blood culture were detected. Conclusion: We report the longest use of APT to maintain extremely preterm fetuses to date. Fetal systemic circulation was maintained without infection, but growth was abnormal. This achievement suggests a need to focus not only on cardiovascular stability and health but also on the optimization of fetal growth and organ development. This new challenge will need to be overcome prior to the clinical translation of this technology.

Haemodynamic effects of inhaled nitric oxide in acute myocardial infarction complicated by right heart failure under ECPELLA support: case report

Background

Recently, mechanical support obtained with the combination of venoarterial extracorporeal membrane oxygenation (VA-ECMO) and an Impella device, together referred to as ECPELLA, has been shown to be effective for acute myocardial infarction with cardiogenic shock. However, methods for withdrawing VA-ECMO in acute myocardial infarction cases complicated by right ventricular dysfunction are yet to be established. Here, we report the effective use of inhaled nitric oxide during the weaning of VA-ECMO from the ECPELLA management of a patient with acute myocardial infarction with cardiogenic shock.

Case summary

An 81-year-old man with an acute extensive anterior wall myocardial infarction with cardiogenic shock was supported with ECPELLA to improve his haemodynamics. During ECPELLA, the Impella device could not maintain sufficient flow. Echocardiography revealed a small left ventricle and an enlarged right ventricle, indicating acute right heart failure. Inhaled nitric oxide was initiated to reduce right ventricle afterload, which decreased pulmonary artery pressure from 34/20 to 27/13 mmHg, improved right and left ventricle sizes, and stabilized the Impella support. Afterward, VA-ECMO could be withdrawn because the Impella alone was sufficient for haemodynamic support.

Discussion

Inhaled nitric oxide improved right ventricle performance in a patient with severe myocardial infarction with right heart failure supported by ECPELLA. Thus, we suggest that inhaled nitric oxide facilitates the weaning of VA-ECMO from patients with refractory right ventricular dysfunction who are supported by ECPELLA.

Factor XII Silencing Using siRNA Prevents Thrombus Formation in a Rat Model of Extracorporeal Life Support

Heparin anticoagulation increases the bleeding risk during extracorporeal life support (ECLS). This study determined whether factor XII (FXII) silencing using short interfering RNA (siRNA) can provide ECLS circuit anticoagulation without bleeding. Adult male, Sprague-Dawley rats were randomized to four groups (n = 3 each) based on anticoagulant: (1) no anticoagulant, (2) heparin, (3) FXII siRNA, or (4) nontargeting siRNA. Heparin was administered intravenously before and during ECLS. FXII or nontargeting siRNA were administered intravenously 3 days before the initiation of ECLS via lipidoid nanoparticles. The rats were placed on pumped, arteriovenous ECLS for 8 hours or until the blood flow resistance reached three times its baseline resistance. Without anticoagulant, mock-oxygenator resistance tripled within 7 ± 2 minutes. The resistance in the FXII siRNA group did not increase for 8 hours. There were no significant differences in resistance or mock-oxygenator thrombus volume between the FXII siRNA and the heparin groups. However, the bleeding time in the FXII siRNA group (3.4 ± 0.6 minutes) was significantly shorter than that in the heparin group (5.5 ± 0.5 minutes, p < 0.05). FXII silencing using siRNA provided simpler anticoagulation of ECLS circuits with reduced bleeding time as compared to heparin. http://links.lww.com/ASAIO/A937.

aPTT-guided anticoagulation monitoring during ECMO support: A systematic review and meta-analysis

INTRODUCTION

The initiation of the extracorporeal membrane oxygenation (ECMO) is associated with complex coagulatory and inflammatory processes and consequently needed anticoagulation. Systemic anticoagulation bears an additional risk of serious bleeding, and its monitoring is of immense importance. Therefore, our work aims to analyze the association of anticoagulation monitoring with bleeding during ECMO support.

MATERIAL AND METHODS

Systematic literature review and meta-analysis, complying with the PRISMA guidelines (PROSPERO-CRD42022359465).

RESULTS

Seventeen studies comprising 3249 patients were included in the final analysis. Patients experiencing hemorrhage had a longer activated partial thromboplastin time (aPTT), a longer ECMO duration, and higher mortality. We could not find strong evidence of any aPTT threshold association with the bleeding occurrence, as less than half of authors reported a potential relationship. Finally, we identified the acute kidney injury (66%, 233/356) and hemorrhage (46%, 469/1046) to be the most frequent adverse events, while almost one-half of patients did not survive to discharge (47%, 1192/2490).

CONCLUSION

The aPTT-guided anticoagulation is still the standard of care in ECMO patients. We did not find strong evidence supporting the aPTT-guided monitoring during ECMO. Based on the weight of the available evidence, further randomized trials are crucial to clarify the best monitoring strategy.

Association of aPTT-Guided Anticoagulation Monitoring with Thromboembolic Events in Patients Receiving V-A ECMO Support: A Systematic Review and Meta-Analysis

BACKGROUND

The initiation of extracorporeal membrane oxygenation (ECMO) is associated with complex inflammatory and coagulatory processes, raising the need for systemic anticoagulation. The balance of anticoagulatory and procoagulant factors is essential, as therapeutic anticoagulation confers a further risk of potentially life-threatening bleeding. Therefore, our study aims to systematize and analyze the most recent evidence regarding anticoagulation monitoring and the thromboembolic events in patients receiving veno-arterial ECMO support.

METHODS

Using the PRISMA guidelines, we systematically searched the Scopus and PubMed databases up to October 2022. A weighted effects model was employed for the meta-analytic portion of the study.

RESULTS

Six studies comprising 1728 patients were included in the final analysis. Unfractionated heparin was used for anticoagulation, with an activated partial thromboplastin time (aPTT) monitoring goal set between 45 and 80 s. The majority of studies aimed to investigate the incidence of adverse events and potential risk factors for thromboembolic and bleeding events. None of the authors found any association of aPTT levels with the occurrence of thromboembolic events. Finally, the most frequent adverse events were hemorrhage (pooled 43%, 95% CI 28.4; 59.5) and any kind of thrombosis (pooled 36%, 95% CI 21.7; 53.7), and more than one-half of patients did not survive to discharge (pooled 54%).

CONCLUSIONS

Despite the tremendous development of critical care, aPTT-guided systemic anticoagulation is still the standard monitoring tool. We did not find any association of aPTT levels with thrombosis. Further evidence and new trials should clarify the true incidence of thromboembolic events, along with the best anticoagulation and monitoring strategy in veno-arterial ECMO patients.

Comparison of bivalirudin versus heparin in adult extracorporeal membrane oxygenation anticoagulant therapy: A retrospective case-control study

INTRODUCTION

There were controversial opinions on the use of bivalirudin versus heparin for anticoagulant therapy in extracorporeal membrane oxygenation. The aim of our present study is to evaluate the efficacy and safety of bivalirudin versus heparin for the maintenance of systemic anticoagulation during adult veno-venous extracorporeal membrane oxygenation (V-V ECMO).

METHODS

Adult patients who received V-V ECMO support in our center between February 2018and February 2022 were retrospectively recruited. We analyzed their ECMO support time, platelet count, coagulation indicators, blood product infusion volume, the incidence of thrombosis and bleeding, probability of successful weaning of ECMO, and in-hospital mortality.

RESULTS

A total of 58 patients received V-V ECMO support. Thirty-four patients were finally included according to the exclusion and inclusion criteria, 14 and 20 accepted bivalirudin and heparin for anticoagulant therapy, respectively. The Minimum platelet value (98.50 × 10⁹/L (85.50, 123.75) vs 49.50 × 10⁹/L (31.25, 83.00), p = 0.002) and mean platelet value (149.90 × 10⁹/L (127.40, 164.80) vs 74.55 × 10⁹/L (62.45, 131.60), p = 0.03) and the ratio of successful weaning of ECMO (92.8% vs 60.0%, p = 0.033) in bivalirudin group were significantly higher than those in heparin group. The red blood cell infusion volume (7.00 U (3.00, 13.25) vs 13.75 U (7.25, 22.63), p = 0.039), platelet infusion volume (0.00 mL (0.00, 75.00) vs 300 mL (0.00, 825.00), p = 0.027), and the incidence of major bleeding (0.00% vs 30%, p = 0.024) in bivalirudin group were significantly lower than those in heparin group.

CONCLUSIONS

In V-V ECMO-supported adult patients, systemic anticoagulation with bivalirudin has achieved the same anticoagulation targets as heparin with less frequency of major bleeding events and lower requirement for blood products without significantly increased risk of thrombosis. Bivalirudin most likely is a safe and effective anticoagulation method for adult patients supported by V-V ECMO.

Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock: Results of the ECMO-CS Randomized Clinical Trial

BACKGROUND

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is increasingly being used for circulatory support in patients with cardiogenic shock, although the evidence supporting its use in this context remains insufficient. The ECMO-CS trial (Extracorporeal Membrane Oxygenation in the Therapy of Cardiogenic Shock) aimed to compare immediate implementation of VA-ECMO versus an initially conservative therapy (allowing downstream use of VA-ECMO) in patients with rapidly deteriorating or severe cardiogenic shock.

METHODS

This multicenter, randomized, investigator-initiated, academic clinical trial included patients with either rapidly deteriorating or severe cardiogenic shock. Patients were randomly assigned to immediate VA-ECMO or no immediate VA-ECMO. Other diagnostic and therapeutic procedures were performed as per current standards of care. In the early conservative group, VA-ECMO could be used downstream in case of worsening hemodynamic status. The primary end point was the composite of death from any cause, resuscitated circulatory arrest, and implementation of another mechanical circulatory support device at 30 days.

RESULTS

A total of 122 patients were randomized; after excluding 5 patients because of the absence of informed consent, 117 subjects were included in the analysis, of whom 58 were randomized to immediate VA-ECMO and 59 to no immediate VA-ECMO. The composite primary end point occurred in 37 (63.8%) and 42 (71.2%) patients in the immediate VA-ECMO and the no early VA-ECMO groups, respectively (hazard ratio, 0.72 [95% CI, 0.46-1.12]; P=0.21). VA-ECMO was used in 23 (39%) of no early VA-ECMO patients. The 30-day incidence of resuscitated cardiac arrest (10.3.% versus 13.6%; risk difference, -3.2 [95% CI, -15.0 to 8.5]), all-cause mortality (50.0% versus 47.5%; risk difference, 2.5 [95% CI, -15.6 to 20.7]), serious adverse events (60.3% versus 61.0%; risk difference, -0.7 [95% CI, -18.4 to 17.0]), sepsis, pneumonia, stroke, leg ischemia, and bleeding was not statistically different between the immediate VA-ECMO and the no immediate VA-ECMO groups.

CONCLUSIONS

Immediate implementation of VA-ECMO in patients with rapidly deteriorating or severe cardiogenic shock did not improve clinical outcomes compared with an early conservative strategy that permitted downstream use of VA-ECMO in case of worsening hemodynamic status.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT02301819.

Keep the Right in Mind-A Focused Approach to Right Ventricle-Predominant Cardiogenic Shock

Cardiogenic shock (CS) remains a highly lethal condition despite many efforts and new interventions. Patients presenting with a rapid onset of hemodynamic instability and subsequent collapse require prompt and appropriate multimodality treatment. Multiple etiologies can lead to heart failure and subsequent shock. As the case prevalence of heart failure increases worldwide, it is of great importance to explore all manners and protocols of presentation and treatment present. With research primarily focusing on CS due to cardiac left-sided pathology, few assessments of right-sided pathology and the subsequent clinical state and treatment have been conducted. This review aims to present an in-depth assessment of the currently available literature, assessing the pathophysiology, presentation and management of CS patients due to right heart failure.

Spinal Cord Infarction With Prolonged Femoral Venoarterial Extracorporeal Membrane Oxygenation

OBJECTIVES

There have been sporadic reports of ischemic spinal cord injury (SCI) during venoarterial extracorporeal membrane oxygenation (VA-ECMO) support. The authors observed a troubling pattern of this catastrophic complication and evaluated the potential mechanisms of SCI related to ECMO.

DESIGN

This study was a case series.

SETTING

This study was performed at a single institution in a University setting.

PARTICIPANTS

Patients requiring prolonged VA-ECMO were included.

INTERVENTIONS

No interventions were done. This was an observational study.

MEASUREMENTS AND MAIN RESULTS

Four hypotheses of etiology were considered: (1) hypercoagulable state/thromboembolism, (2) regional hypoxia/hypocarbia, (3) hyperperfusion and spinal cord edema, and (4) mechanical coverage of spinal arteries. The SCI involved the lower thoracic (T7-T12 level) spinal cord to the cauda equina in all patients. Seven out of 132 (5.3%) patients with prolonged VA-ECMO support developed SCI. The median time from ECMO cannulation to SCI was 7 (range: 6-17) days.There was no evidence of embolic SCI or extended regional hypoxia or hypocarbia. A unilateral, internal iliac artery was covered by the arterial cannula in 6/7 86%) patients, but flow into the internal iliac was demonstrated on imaging in all available patients. The median total flow (ECMO + intrinsic cardiac output) was 8.5 L/min (LPM), and indexed flow was 4.1 LPM/m². The median central venous oxygen saturation was 88%, and intracranial pressure was measured at 30 mmHg in one patient, suggestive of hyperperfusion and spinal cord edema.

CONCLUSIONS

An SCI is a serious complication of extended peripheral VA-ECMO support. Its etiology remains uncertain, but the authors' preliminary data suggested that spinal cord edema from hyperperfusion or venous congestion could contribute.

Perioperative extracorporeal membrane oxygenation in pediatric congenital heart disease: Chinese expert consensus

BACKGROUND

Congenital heart disease (CHD) is one of the main supportive diseases of extracorporeal membrane oxygenation in children. The management of extracorporeal membrane oxygenation (ECMO) for pediatric CHD faces more severe challenges due to the complex anatomical structure of the heart, special pathophysiology, perioperative complications and various concomitant malformations. The survival rate of ECMO for CHD was significantly lower than other classifications of diseases according to the Extracorporeal Life Support Organization database. This expert consensus aims to improve the survival rate and reduce the morbidity of this patient population by standardizing the clinical strategy.

METHODS

The editing group of this consensus gathered 11 well-known experts in pediatric cardiac surgery and ECMO field in China to develop clinical recommendations formulated on the basis of existing evidences and expert opinions.

RESULTS

The primary concern of ECMO management in the perioperative period of CHD are patient selection, cannulation strategy, pump flow/ventilator parameters/vasoactive drug dosage setting, anticoagulation management, residual lesion screening, fluid and wound management and weaning or transition strategy. Prevention and treatment of complications of bleeding, thromboembolism and brain injury are emphatically discussed here. Special conditions of ECMO management related to the cardiovascular anatomy, haemodynamics and the surgical procedures of common complex CHD should be considered.

CONCLUSIONS

The consensus could provide a reference for patient selection, management and risk identification of perioperative ECMO in children with CHD. Video abstract (MP4 104726 kb).

Central extracorporeal circulatory life support (cECLS) in selected patients with critical cardiogenic shock

Background

Percutaneous extracorporeal life support (pECLS) is increasingly applied in cardiogenic shock (CS) despite a lack of evidence from randomized trials. The in-hospital mortality rate of pECLS still reaches up to 60%, while vascular access site complications remain a shortcoming. Surgical approaches with central cannulation for ECLS (cELCS) have emerged as a bail-out option. To date, no systematic approach exists that allows a definition of inclusion or exclusion criteria for cECLS.

Methods and results

This single-center, retrospective, case-control study includes all patients fulfilling criteria for CS at the West German Heart and Vascular Center Essen/Germany between 2015 and 2020 who underwent cECLS (n = 58), excluding post-cardiotomy patients. Seventeen patients received cECLS (29.3%) as a first-line treatment strategy and 41 patients as a second-line strategy (70.7%). The main complications leading to the use of cECLS as a second-line strategy were limb ischemia (32.8%) and ongoing insufficient hemodynamic support (27.6%). The first-line cECLS cohort showed a 30-day mortality rate of 53.3% that was constant during follow-up. The 30-day mortality rate of secondary cECLS candidates was 69.8% and the rate at 3 and 6 months was 79.1%. Younger patients (<55 years) were more likely to exhibit survival benefit with cECLS (p = 0.043).

Conclusion

Surgical cECLS in CS is a feasible therapy for highly selected patients with hemodynamic instability, vascular complications, or peripheral access site limitations as complementary strategy in experienced centers.

Factor XI/XIa Inhibition: The Arsenal in Development for a New Therapeutic Target in Cardio- and Cerebrovascular Disease

Despite major advancements in the development of safer and more effective anticoagulant agents, bleeding complications remain a significant concern in the treatment of thromboembolic diseases. Improvements in our understanding of the coagulation pathways highlights the notion that the contact pathway-specifically factor XI (FXI)-has a greater role in the etiopathogenesis of thrombosis than in physiological hemostasis. As a result, a number of drugs targeting FXI are currently in different stages of testing and development. This article aims to review the different strategies directed towards FXI-inhibition with a brief summation of the agents in clinical development, and to comment on the therapeutic areas that could be explored for potential indications. Therapeutics targeting FXI/FXIa inhibition have the potential to usher in a new era of anticoagulation therapy.

Incidence of Venous Thromboembolism in Adults Receiving Extracorporeal Membrane Oxygenation: A Systematic Review

Extracorporeal membrane oxygenation (ECMO) has become an increasingly used tool for cardiorespiratory support. Thrombosis is a well-recognized complication of ECMO, yet the burden of disease remains unclear. We undertook a systematic review to investigate the incidence of venous thromboembolism (VTE) during ECMO or soon after decannulation, in patients screened for VTE. We retrieved all studies that evaluated VTE incidence in ECMO patients in EMBASE, MEDLINE, Web of Science, and Cochrane Library from inception to April 2, 2021. Studies reporting incidence of VTE diagnosed on systematic screening tests during ECMO or within 7 days of decannulation in adult patients were included. A total of 18 studies were included in the systematic review. These studies screened a total of 1095 ECMO patients. Most studies screened for cannula-associated deep vein thrombosis (CaDVT) after decannulation. The overall incidence of DVT was 52.8% (95% CI, 49.8-55.8%). Incidence of DVT was 53.5% (95% CI, 50.0-57.0%) for venovenous ECMO vs. 34.0% (95% CI, 26.5-42.2%) for venoarterial ECMO. No studies screened for pulmonary embolism. Our systematic review found a very high incidence of DVT among patients treated with ECMO. Routine screening for DVT after decannulation for all ECMO patients may be warranted.

Satisfactory outcome with activated clotting time <160 seconds in extracorporeal cardiopulmonary resuscitation

Patients undergoing cardiopulmonary resuscitation (CPR) prior to extracorporeal membrane oxygenation (ECMO) can have severely altered physiology, including that of the coagulation pathway. This could complicate the extracorporeal cardiopulmonary resuscitation (ECPR) management. We aimed to show that targeting an activated clotting time (ACT) < 160 seconds does not affect the complication rates in these patients. In this single-centered retrospective study, the medical records of 81 adult patients who were on ECMO support from March 2017 to March 2020 were reviewed. We compared the low ACT and conventional ACT groups, which were defined on the basis of the median of the ACT values of the included patients (160 seconds). The primary outcomes included bleeding or thromboembolic events. This study included 32 patients, who were divided into the low (n = 14) and conventional (n = 18) ACT groups. There were 2 cases of gastrointestinal bleeding (P = .183), one of intracranial hemorrhage (P = .437), and one of peripheral skin color change (P = .437) in the low ACT group. There was one case of prolonged bleeding at the cannulation site (P = 1.000) reported in the conventional ACT group. The successful weaning rate differed significantly between the low and conventional ACT groups (92.9% vs 50.0%; P = .019). Maintaining the ACT lower than the conventional ACT in patients requiring ECPR did not show a significant increase in the thromboembolic risk. Therefore, targeting a low ACT should be considered for this particular group of patients.

Extremity fasciotomy for patients on extracorporeal membrane oxygenation is independently associated with inpatient mortality

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) maintains end-organ perfusion in critically ill patients with cardiac or respiratory failure; however, ECMO cannulation in the extremities has been associated with significant limb ischemia and risk of compartment syndrome. Current literature on ECMO and fasciotomies is limited to small single-center retrospective studies. This study aimed to (1) compare the incidence of postoperative outcomes and mortality in patients undergoing fasciotomy while on ECMO to those of non-fasciotomy ECMO patients, and (2) assess the difference in adjusted mortality risk between the two groups.

HYPOTHESIS

We hypothesized that patients undergoing fasciotomy while on ECMO would have significantly higher odds of in-hospital mortality than non-fasciotomy ECMO patients after adjustment for perioperative variables.

METHODS

We conducted a retrospective review of NIS from January 1st, 2012-September 30, 2015 for all hospitalizations involving ECMO and stratified them into two cohorts based on whether they underwent fasciotomy after ECMO. Patient baseline characteristics, in-hospital procedures, and postoperative outcomes were compared between the two cohorts. Logistic regression was used to assess in-hospital mortality risk between the two cohorts adjusting for age, sex, Elixhauser score, and perioperative procedures and non-fasciotomy perioperative morbidity.

RESULTS

There were 7,085 estimated eligible discharges between 2012 and 2015 identified, 149 (2.1%) of which underwent fasciotomy following ECMO. One hundred and thirteen of the 149 hospitalizations (77%) in the fasciotomy cohort resulted in in-hospital mortality, compared to 3,805 of the 6,936 (55%) in the non-fasciotomy cohort. There were no differences in rates of transfusion (p=0.290), length of stay (p=0.282), or discharge disposition (p=0.126) between the two cohorts. In the logistic regression model, the fasciotomy cohort had a higher odds of in-hospital mortality than non-fasciotomy cohort (OR, 2.5; 95% CI, 1.1-5.6).

DISCUSSION

Operative treatment of acute compartment syndrome for patients on ECMO therapy is associated with significantly increased mortality and morbidity. Whether fasciotomy is a marker of sickness or represents a cause-and-effect relationship is unknown and future should investigate the role of non-operative treatment of compartment syndrome on mortality in this population.

LEVEL OF EVIDENCE

III; Prognostic.

Prevalence and outcomes of patients developing heparin-induced thrombocytopenia during extracorporeal membrane oxygenation

Objectives

Unfractionated heparin (UFH) is the commonly used anticoagulant to prevent clotting of the ECMO circuit and thrombosis of the cannulated vessels. A side effect of UFH is heparin-induced thrombocytopenia (HIT). Little is known about HIT during ECMO and the impact of changing anticoagulation in ECMO patients with newly diagnosed HIT. The aim of the study was to determine the prevalence, complications, impact of switching anticoagulation to argatroban and outcomes of patients developing heparin-induced thrombocytopenia (HIT) during either veno-venous (VV) or veno-arterial (VA) ECMO.

Methods

Retrospective observational single centre study of prospectively collected data of consecutive patients receiving VV ECMO therapy for severe respiratory failure and VA ECMO for circulatory failure from January 2006 to December 2016 of the Medical intensive care unit (ICU) of the University Hospital of Regensburg. Treatment of HIT on ECMO was done with argatroban.

Results

507 patients requiring ECMO were included. Further HIT-diagnostic was conducted if HIT-4T-score was ≥4. The HIT-confirmed group had positive HIT-enzyme-linked-immunosorbent-assay (ELISA) and positive heparin-induced-platelet-activation (HIPA) test, the HIT-suspicion group a positive HIT-ELISA and missing HIPA but remained on alternative anticoagulation until discharge and the HIT-excluded group a negative or positive HIT-ELISA, however negative HIPA. These were compared to group ECMO-control without any HIT suspicion. The prevalence of HIT-confirmed was 3.2%, of HIT-suspicion 2.0% and HIT-excluded 10.8%. Confirmed HIT was trendwise more frequent in VV than in VA (3.9 vs. 1.7% p = 0.173). Compared to the ECMO control group, patients with confirmed HIT were longer on ECMO (median 13 vs. 8 days, p = 0.002). Different types of complications were higher in the HIT-confirmed than in the ECMO-control group, but in-hospital mortality was not different (31% vs. 41%, p = 0.804).

Conclusion

HIT is rare on ECMO, should be suspected, if platelets are decreasing, but seems not to increase mortality if treated promptly.

Poor Outcomes of Pediatric Acute Compartment Syndrome in the Setting of Extracorporeal Membrane Oxygenation: A Multicenter Case Series

BACKGROUND

Acute compartment syndrome (ACS) is a well-described condition that merits emergent surgical decompression. Peripheral arterial cannulation can increase the likelihood of ACS in patients requiring extracorporeal membranous oxygen (ECMO). Comorbidities in these critically ill patients may portend negative consequences of decompressive fasciotomy. This study investigated the clinical short-term and mid-term outcomes in pediatric patients with ECMO-associated ACS.

METHODS

This is a retrospective case series at 3 pediatric hospitals from 2006 to 2019, including children ages 0 to 19 years who underwent peripheral arterial cannulation and developed ACS.

RESULTS

Eighteen patients developed ACS after receiving peripheral cannulation ECMO. Mean time to diagnosis after cannulation was 63.1 hours. All patients were diagnosed clinically; the most common findings were tight compartments, swelling, and loss of peripheral pulses. Eight patients (44%) died due to underlying illness. Treating physicians decided against decompression for 5 patients due to their underlying illness, instability, and concern for infection. Thirteen patients (72%) underwent decompressive fasciotomies. Ten surgical patients required subsequent surgeries and 6 (33%) developed surgical site infections. Of the 7 surviving surgical patients, 4 (57%) required extremity amputations and 4 had lower extremity neurological deficits on follow-up. Two of 3 nonsurgical patients (66%) had functional lower extremity motor deficits on follow-up. No surviving nonoperative patients developed infections or required amputations.

CONCLUSIONS

ACS on ECMO is associated with high rates of complications including neurologic deficits, infection, and amputation. Patients treated nonoperatively avoided complications such as infection and amputation, but had more functional neurological deficits than surgical patients. Orthopaedic surgeons should consider the high morbidity of compartment release in these critically ill patients and, with critical care teams, assess whether the potential benefits of surgery outweigh expected risks.

LEVEL OF EVIDENCE

Level IV.

Anesthetic Management of Upper Tracheal Cancer Resection and Reconstruction: A Case Report

Tracheal tumor resection and reconstruction is the primary treatment for tracheal tumors. The trachea is the surgical site as well as an important channel to ensure ventilation and maintain oxygenation during surgery. In this report, we describe the successful management of an upper tracheal tumor in a 50-year-old patient. The tumor was situated approximately 2–3 cm below the vocal cords, occluding the tracheal lumen by 80%. Conventional orotracheal intubation was expected to be impossible, and the patient was managed with an I-Gel supraglottic airway for mechanical ventilation with the assistance of venovenous extracorporeal membrane oxygenation (VV ECMO). After securing tracheal intubation via the tracheostomy site, VV ECMO was weaned off, and mechanical ventilation was changed to tracheal intubation. Eventually, tracheal tumor resection and reconstruction were successfully performed under general anesthesia. No specific events occurred during anesthetic management. Careful preoperative planning and good teamwork made the procedure possible without complications.

A Comparison of Activated Partial Thromboplastin Time and Activated Coagulation Time for Anticoagulation Monitoring during Extracorporeal Membrane Oxygenation Therapy

BACKGROUND

 Unfractionated heparin is used to prevent coagulation activation in patients undergoing extracorporeal membrane oxygenation (ECMO) support. We designed this study to determine the preferable indicator for anticoagulation monitoring.

METHODS

 We conducted a retrospective study and divided the patients into an activated coagulation time (ACT)-target group and an activated partial thromboplastin time (aPTT)-target group. The correlations between ACT, aPTT, and the heparin dose were explored.

RESULTS

 Thirty-six patients were included (19 aPTT-target and 17 ACT-target patients); a total of 555 matched pairs of ACT/aPTT results were obtained. The correlation between the ACT and aPTT measurements was Spearman's Rank Correlation Coefficient (rs) = 0.518 in all 555 pairs. The Bland-Altman plot showed data points outside the displayed range (51.2-127.7), suggesting that the agreement between ACT and aPTT was poor. The aPTT group had fewer heparin dose changes (2.12 ± 0.68 vs. 2.57 ± 0.64, p = 0.05) and a lower cumulative heparin dose (317.6 ± 108.5 vs. 396.3 ± 144.3, p = 0.00) per day than the ACT group. There was no difference in serious bleeding (9 vs. 5; p = 0.171) or embolism events (3 vs. 3; p = 1.0) or in the red blood cell and fresh frozen plasma transfusion volumes between the ACT- and aPTT-target groups. Similarly, there was no significant difference in the ECMO duration (9 [4-15] days vs. 4 [3-14] days; p = 0.124) or length of ICU hospitalization (17 [5-32] days vs. 13 [4-21] days; p = 0.451) between the groups.

CONCLUSION

 The correlation between ACT and aPTT and the heparin dose was poor. The aPTT group had fewer daily heparin dose changes and a lower cumulative heparin dose per day than the ACT group, with no more bleeding and thrombotic events. Therefore, we recommend aPTT rather than ACT to adjust heparin dose in the absence of better monitoring indicators.

Heparin-free after 3000 IU heparin loaded in veno-venous ECMO supported acute respiratory failure patients with hemorrhage risk: a novel anti-coagulation strategy

Background

The anti-coagulation protocol of patients with hemorrhage risk primary disease who need extracorporeal membrane oxygenation (ECMO) supported is controversial. This study evaluated the feasibility of a new anti-coagulation strategy, that is heparin-free after 3000 IU heparin loaded in veno-venous ECMO (VV ECMO) supported acute respiratory failure patients with hemorrhage risk.

Methods

A retrospective study was performed in a series of hemorrhage risk patients supported with VV ECMO at the First Affiliated Hospital of Zhengzhou University, between June 2012 to Sept 2020. A total of 70 patients received a low heparin bolus of 3000 units for cannulation but without subsequent, ongoing heparin administration. Patients were divided into survival (n = 25) and non-survival group (n = 45). Data of coagulation, hemolysis and membrane lung function were calculated and analyzed. The complications of patients were recorded. Finally, the binary Logistic regression was conducted.

Results

The longest heparin-free time was 216 h, and the mean heparin-free time was 102 h. Compared with survivors, the non-survivors were showed higher baseline SOFA score and lower platelet counts in 0.5 h, 24 h, 48 h and 96 h after ECMO applied. However, there was no significant differences between survivors and non-survivors in ACT, APTT, INR, D-dimer, fibrinogen, LDH, blood flow rate, Δp and P_post-MLO₂ (all p < 0.05) of all different time point. Moreover, only the baseline SOFA score was significantly associated with mortality (p < 0.001, OR(95%CI): 2.754 (1.486–5.103)) while the baseline levels of ACT, APTT, INR, platelet, D-dimer, fibrinogen and LDH have no association with mortality. The percentage of thrombosis complications was 54.3% (38/70) including 3 oxygenator changed but there was no significant difference of complications in survival and non-survival groups (p > 0.05).

Conclusions

The anticoagulation protocol that no heparin after a 3000 units heparin bolus in VV ECMO supported acute respiratory failure patients with hemorrhage risk is feasible.

Mechanical Circulatory Support for Right Ventricular Failure

Right ventricular (RV) failure is associated with significant morbidity and mortality, with in-hospital mortality rates estimated as high as 70–75%. RV failure may occur following cardiac surgery in conjunction with left ventricular failure, or may be isolated in certain circumstances, such as inferior MI with RV infarction, pulmonary embolism or following left ventricular assist device placement. Medical management includes volume optimisation and inotropic and vasopressor support, and a subset of patients may benefit from mechanical circulatory support for persistent RV failure. Increasingly, percutaneous and surgical mechanical support devices are being used for RV failure. Devices for isolated RV support include percutaneous options, such as micro-axial flow pumps and extracorporeal centrifugal flow RV assist devices, surgically implanted RV assist devices and veno-arterial extracorporeal membrane oxygenation. In this review, the authors discuss the indications, candidate selection, strategies and outcomes of mechanical circulatory support for RV failure.

Aptamer-based factor IXa inhibition preserves hemostasis and prevents thrombosis in a piglet model of ECMO

Extracorporeal membrane oxygenation (ECMO) requires anticoagulation to prevent clotting when the patient’s blood contacts the circuit. Unfractionated heparin (UFH) usually prevents clotting but can cause life-threatening bleeding. An anticoagulant that selectively inhibits the contact activation (intrinsic) pathway while sparing the tissue factor (extrinsic) pathway of coagulation might prevent clotting triggered by the circuit while permitting physiologic coagulation at surgical sites. DTRI-178 is an RNA anticoagulant aptamer conjugated to polyethylene glycol that increases its half-life in circulation. This aptamer is based on a previously described molecule (9.3t) that inhibits intrinsic tenase activity by binding to factor IXa on an exosite. Using a piglet model of pediatric venoarterial (VA) ECMO, we compared thromboprevention and blood loss using a single dose of DTRI-178 versus UFH. In each of five experiments, we subjected two litter-matched piglets, one anticoagulated with DTRI-178 and the other with UFH, to simultaneous 12-h periods of VA ECMO. Both anticoagulants achieved satisfactory and comparable thromboprotection. However, UFH piglets had increased surgical site bleeding and required significantly greater blood transfusion volumes than piglets anticoagulated with DTRI-178. Our results indicate that DTRI-178, an aptamer against factor IXa, may be feasible, safer, and result in fewer transfusions and clinical bleeding events in ECMO.

Risk assessment of venous thromboembolism and bleeding in COVID-19 patients

BACKGROUND

The coronavirus disease 2019 (COVID-19) is a newly recognized illness that has spread rapidly all over the world. More and more reports highlight the risk of venous thromboembolism (VTE) in COVID-19. Our study aims to identify in-hospital VTE risk and bleeding risk in COVID-19 patients.

METHODS

We retrospectively studied 138 consecutively enrolled patients with COVID-19 and identified in-hospital VTE and bleeding risk by Padua Prediction Score and Improve bleed risk assessment model. The clinical data and features were analyzed in VTE patients.

RESULTS

Our findings identified that 23 (16.7%) patients with COVID-19 were at high risk for VTE according to Padua prediction score and 9 (6.5%) patients were at high risk of bleeding for VTE prophylaxis according to Improve prediction score. Fifteen critically ill patients faced double high risk from thrombosis (Padua score more than 4 points in all 15 [100%] patients) and hemorrhage (Improve score more than 7 points in 9 [60.0%] patients). Thrombotic events were identified in four patients (2.9%) of all COVID-19 patients. All of them were diagnosed with deep vein thrombosis by ultrasound 3 to 18 days after admission. Three (75.0%) were critically ill patients, which means that the incidence of VTE among critically ill patients was 20%. One major hemorrhage happened in critically ill patients during VTE treatment.

CONCLUSION

Critically ill patients with COVID-19 suffered both a high risk of thrombosis and bleeding risks. More effective VTE prevention strategies based on an individual assessment of bleeding risks were necessary for critically ill patients with COVID-19.

Extracorporeal Membrane Oxygenation in Infarct-Related Cardiogenic Shock

Mortality in infarct-related cardiogenic shock (CS) remains high, reaching 40–50%. In refractory CS, active mechanical circulatory support devices including veno-arterial extracorporeal membrane oxygenation (VA-ECMO) are rapidly evolving. However, supporting evidence of VA-ECMO therapy in infarct-related CS is low. The current review aims to give an overview on the basics of VA-ECMO therapy, current evidence, ongoing trials, patient selection and potential complications.

Mortality in cardiogenic shock patients receiving mechanical circulatory support: a network meta-analysis

Objective

Mechanical circulatory support (MCS) devices are widely used for cardiogenic shock (CS). This network meta-analysis aims to evaluate which MCS strategy offers advantages.

Methods

A systemic search of PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials was performed. Studies included double-blind, randomized controlled, and observational trials, with 30-day follow-ups. Paired independent researchers conducted the screening, data extraction, quality assessment, and consistency and heterogeneity assessment.

Results

We included 39 studies (1 report). No significant difference in 30-day mortality was noted between venoarterial extracorporeal membrane oxygenation (VA-ECMO) and VA-ECMO plus Impella, Impella, and medical therapy. According to the surface under the cumulative ranking curve, the optimal ranking of the interventions was surgical venting plus VA-ECMO, medical therapy, VA-ECMO plus Impella, intra-aortic balloon pump (IABP), Impella, Tandem Heart, VA-ECMO, and Impella plus IABP. Regarding in-hospital mortality and 30-day mortality, the forest plot showed low heterogeneity. The results of the node-splitting approach showed that direct and indirect comparisons had a relatively high consistency.

Conclusions

IABP more effectively reduce the incidence of 30-day mortality compared with VA-ECMO and Impella for the treatment of CS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02493-0.

Longitudinal Trends in Bleeding Complications on Extracorporeal Life Support Over the Past Two Decades—Extracorporeal Life Support Organization Registry Analysis

OBJECTIVES

Data about inhospital outcomes in bleeding complications during extracorporeal life support (ECLS) have been poorly investigated.

DESIGN

Retrospective observational study.

SETTING

Patients reported in Extracorporeal Life Support Organization Registry.

PATIENTS

Data of 53.644 adult patients (greater than or equal to 18 yr old) mean age 51.4 ± 15.9 years, 33.859 (64.5%) male supported with single ECLS run between 01.01.2000 and 31.03.2020, and 19.748 cannulated for venovenous (V-V) ECLS and 30.696 for venoarterial (V-A) ECLS.

INTERVENTIONS

Trends in bleeding complications, bleeding risk factors, and mortality.

MEASUREMENT AND MAIN RESULTS

Bleeding complications were reported in 14.786 patients (27.6%), more often in V-A ECLS compared with V-V (30.0% vs 21.9%; p < 0.001). Hospital survival in those who developed bleeding complications was lower in both V-V ECLS (49.6% vs 66.6%; p < 0.001) and V-A ECLS (33.9 vs 44.9%; p < 0.001). Steady decrease in bleeding complications in V-V and V-A ECLS was observed over the past 20 years (coef., -1.124; p < 0.001 and -1.661; p < 0.001). No change in mortality rates was reported over time in V-V or V-A ECLS (coef., -0.147; p = 0.442 and coef., -0.195; p = 0.139).Multivariate regression revealed advanced age, ecls duration, surgical cannulation, renal replacement therapy, prone positioning as independent bleeding predictors in v-v ecls and female gender, ecls duration, pre-ecls arrest or bridge to transplant, therapeutic hypothermia, and surgical cannulation in v-a ecls.

CONCLUSIONS

A steady decrease in bleeding over the last 20 years, mostly attributable to surgical and cannula-site-related bleeding has been found in this large cohort of patients receiving ECLS support. However, there is not enough data to attribute the decreasing trends in bleeding to technological refinements alone. Especially reduction in cannulation site bleeding is also due to changes in timing, patient selection, and ultrasound guided percutaneous cannulation. Other types of bleeding, such as CNS, have remained stable, and overall bleeding remains associated with a persistent increase in mortality.

Basics of Extracorporeal Membrane Oxygenation

OVERVIEW

The use of extracorporeal membrane oxygenation (ECMO) is becoming commonplace worldwide in ICUs for the care of patients with respiratory and/or cardiac failure. Understanding the use of ECMO and the management of these complex patients will be vital to current and future clinicians as ECMO use continues to grow.

Inpatient Management of Pulmonary Embolism: Clinical Characteristics and Mortality in a High-Volume Tertiary Care Center

The optimal management strategy for submassive or intermediate risk pulmonary embolism (IRPE)-anticoagulation alone versus anticoagulation plus advanced therapies-remains in equipoise leading many institutions to create multidisciplinary PE response teams (PERTs) to guide therapy. Cause-specific mortality of IRPE has not been thoroughly examined, which is a meaningful outcome when examining the effect of specific interventions for PE. In this retrospective study, we reviewed all adult inpatient admissions between 8/1/2018 and 8/1/2019 with an encounter diagnosis of PE to study all cause and PE cause specific mortality as the primary outcomes and bleeding complications from therapies as a secondary outcome. There were 429 total inpatient admissions, of which 59.7% were IRPE. The IRPE 30-day all-cause mortality was 8.7% and PE cause-specific mortality was 0.79%. Treatment consisted of anticoagulation alone in 93.4% of cases. Advanced therapies-systemic thrombolysis, catheter directed thrombolysis, or mechanical thrombectomy, were performed in only six IRPE cases (2.3%). Decompensation of IRPE cases requiring higher level of care and/or rescue advanced therapy occurred in only five cases (2%). In-hospital major bleeding and clinically relevant non-major bleeding were more common in those receiving systemic thrombolysis (61.5%) compared to anticoagulation combined with other advanced therapies (11.7%). Despite the high overall acuity of PE cases at our institution, in-hospital all-cause mortality was low and cause-specific mortality for IRPE was rare. These data suggest the need to target other clinically meaningful outcomes when examining advanced therapies for IRPE.

Soluble thrombomodulin ameliorates aberrant hemostasis after rewarming in a rat accidental hypothermia model

BACKGROUND

Accidental hypothermia (AH) sometimes leads to coagulation disorder, especially in severe AH. We previously demonstrated that intrasplenic platelet activation caused aberrant hemostasis and thrombus formation after rewarming in a murine AH model. However, no study has focused on the appropriate management of platelets causing coagulation activation after rewarming of AH. We investigated whether or not recombinant soluble thrombomodulin (rTM) can suppress thrombosis formation after rewarming using a rat AH model.

METHODS

Wistar rats were exposed to an ambient temperature of -20 °C under general anesthesia until their rectal temperature decreased to 26 °C. The Hypo group rats (n = 5) were immediately euthanized, while the Hypo/Re group (n = 5) and rTM group rats (n = 5), which were administered rTM (1 mg/kg) via the tail vein, were rewarmed until the rectal temperature returned to 34 °C and then euthanized 6 h later. Tissue and blood samples were collected from all rats for histopathological and coagulation analyses at euthanasia.

RESULTS

There was no significant change in the D-dimer level in the Hypo group rats, while the D-dimer level was significantly elevated at 6 h after rewarming in the Hypo/Re group rats (P = 0.015), and histopathology detected both fibrin and platelets in the renal glomerulus. However, the rTM group rats did not show any elevation of the D-dimer levels at 6 h after rewarming, and no fibrin was noted on histopathology.

CONCLUSIONS

rTM may be useful as an appropriate anticoagulant in cases of aberrant hemostasis after rewarming of AH.

Clinical Features and Risk Factors Analysis for Hemorrhage in Adults on ECMO

Background: The use of extracorporeal membrane oxygenation (ECMO) to support critically ill patients with cardiorespiratory dysfunction has increased over the last decades. However, hemorrhagic complications occur frequently during ECMO support, and this has a significant impact on morbidity and mortality. Thus, this study aimed to identify the risk factors for hemorrhage in patients receiving ECMO.

Methods: Our retrospective study included 60 patients, who were admitted to the Taihe Hospital in Shiyan City, Hubei Province, China from February 2017 to October 2020. About 18 patients developed hemorrhagic complications, and 42 patients did not demonstrate such complications. Data regarding patient demography, laboratory tests, and clinical manifestations prior to ECMO were collected to analyze their clinical features. Univariable and multivariable logistic analyses were used to explore the risk factors for hemorrhage in adults on ECMO. The receiver operating characteristic (ROC) curve was used to evaluate the predictive value of the binary logistic model. The amount of blood transfusions was compared between the two groups, and the activated partial thromboplastin time (APTT), platelet count, and hemoglobin level before the initiation of ECMO.

Results: Logistic analysis showed that a longer duration of ECMO support, higher APTT, and lower platelet count prior to ECMO were independent risk factors for hemorrhage in adults on ECMO. In addition, we found that the cannula site was the most common bleeding site. Most bleeding events occurred within the first 3 days of ECMO therapy. After the ECMO initiation, APTT was prolonged while the platelet count and hemoglobin levels were decreased. The amount of blood transfusion was significantly higher in the hemorrhage group than in the non-hemorrhage group.

Conclusions: Clinicians should evaluate the risk of hemorrhage based on the coagulation function of patients, underlying disease, and the duration of ECMO support. In the first 3 days during ECMO support, special attention should be given to the cannula site, mucosal, and dermal regions, and digestive tract to detect any signs of hemorrhage. Moreover, increasing the platelet count transfusion threshold and accurately determining the amount of blood transfusion required may prevent bleeding events.